gist.md

function ee_custom_messaging_changes( $translated, $original, $domain ) {
    $strings = array(
        'upcoming' => 'Próximamente',
        'Upcoming' => 'Próximamente',
    );
    if ( isset( $strings[$original] ) ) {
        $translations = get_translations_for_domain( $domain );
        $translated = $translations->translate( $strings[$original] );
    }
    return $translated;
}
add_filter( 'gettext', 'ee_custom_messaging_changes', 10, 3 );